from datetime import datetime, timedelta, timezone
import falcon
import mysql.connector
import simplejson as json
import config
from core.useractivity import user_logger, admin_control, access_control, api_key_control


class NotificationCollection:
    """
    Notification Collection Resource

    This class handles CRUD operations for notification collection.
    It provides endpoints for listing all notifications and creating new notifications.
    Notifications are alerts and messages displayed to users in the energy management system.
    """
    def __init__(self):
        """Initialize NotificationCollection"""
        pass

    @staticmethod
    def on_options(req, resp):
        """Handle OPTIONS requests for CORS preflight"""
        _ = req
        resp.status = falcon.HTTP_200

    @staticmethod
    def on_get(req, resp):
        if 'API-KEY' not in req.headers or \
                not isinstance(req.headers['API-KEY'], str) or \
                len(str.strip(req.headers['API-KEY'])) == 0:
            access_control(req)
        else:
            api_key_control(req)
        status = req.params.get('status')
        start_datetime_local = req.params.get('startdatetime')
        end_datetime_local = req.params.get('enddatetime')
        if status is not None:
            status = str.strip(status)
            if status not in ['unread', 'read', 'archived']:
                raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                       description='API.INVALID_STATUS')

        timezone_offset = int(config.utc_offset[1:3]) * 60 + int(config.utc_offset[4:6])
        if config.utc_offset[0] == '-':
            timezone_offset = -timezone_offset
        start_datetime_utc = None
        if start_datetime_local is not None and len(str.strip(start_datetime_local)) > 0:
            start_datetime_local = str.strip(start_datetime_local)
            try:
                start_datetime_utc = datetime.strptime(start_datetime_local,
                                                       '%Y-%m-%dT%H:%M:%S').replace(tzinfo=timezone.utc) - \
                                     timedelta(minutes=timezone_offset)
            except ValueError:
                raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                       description="API.INVALID_START_DATETIME")

        end_datetime_utc = None
        if end_datetime_local is not None and len(str.strip(end_datetime_local)) > 0:
            end_datetime_local = str.strip(end_datetime_local)
            try:
                end_datetime_utc = datetime.strptime(end_datetime_local,
                                                     '%Y-%m-%dT%H:%M:%S').replace(tzinfo=timezone.utc) - \
                                        timedelta(minutes=timezone_offset)
            except ValueError:
                raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                       description="API.INVALID_END_DATETIME")

        if start_datetime_utc is not None and end_datetime_utc is not None and \
                start_datetime_utc >= end_datetime_utc:
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.INVALID_END_DATETIME')

        # Verify User Session
        token = req.headers.get('TOKEN')
        user_uuid = req.headers.get('USER-UUID')
        if token is None:
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.TOKEN_NOT_FOUND_IN_HEADERS_PLEASE_LOGIN')
        if user_uuid is None:
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.USER_UUID_NOT_FOUND_IN_HEADERS_PLEASE_LOGIN')

        cnx = mysql.connector.connect(**config.myems_user_db)
        cursor = cnx.cursor()

        query = (" SELECT utc_expires "
                 " FROM tbl_sessions "
                 " WHERE user_uuid = %s AND token = %s")
        cursor.execute(query, (user_uuid, token,))
        row = cursor.fetchone()

        if row is None:
            if cursor:
                cursor.close()
            if cnx:
                cnx.close()
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.INVALID_SESSION_PLEASE_RE_LOGIN')
        else:
            utc_expires = row[0]
            if datetime.utcnow() > utc_expires:
                if cursor:
                    cursor.close()
                if cnx:
                    cnx.close()
                raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                       description='API.USER_SESSION_TIMEOUT')

        cursor.execute(" SELECT id "
                       " FROM tbl_users "
                       " WHERE uuid = %s ",
                       (user_uuid,))
        row = cursor.fetchone()
        if row is None:
            if cursor:
                cursor.close()
            if cnx:
                cnx.close()
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.INVALID_USER_PLEASE_RE_LOGIN')
        else:
            user_id = row[0]

        # get notifications
        if status is None:
            query = (" SELECT id, created_datetime_utc, status, subject, message, url "
                     " FROM tbl_notifications "
                     " WHERE user_id = %s AND "
                     "       created_datetime_utc >= %s AND created_datetime_utc < %s AND"
                     "       status != 'archived' "
                     " ORDER BY created_datetime_utc DESC ")
            cursor.execute(query, (user_id, start_datetime_utc, end_datetime_utc))
        else:
            query = (" SELECT id, created_datetime_utc, status, subject, message, url "
                     " FROM tbl_notifications "
                     " WHERE user_id = %s AND "
                     "       created_datetime_utc >= %s AND created_datetime_utc < %s AND "
                     "       status = %s "
                     " ORDER BY created_datetime_utc DESC ")
            cursor.execute(query, (user_id, start_datetime_utc, end_datetime_utc, status))
        rows = cursor.fetchall()

        if cursor:
            cursor.close()
        if cnx:
            cnx.close()

        result = list()
        if rows is not None and len(rows) > 0:
            for row in rows:
                meta_result = {"id": row[0],
                               "created_datetime":
                                   (row[1] +
                                    timedelta(hours=int(config.utc_offset[1:3]))).isoformat()[0:19],
                               "status": row[2],
                               "subject": row[3],
                               "message": row[4],
                               "url": row[5]}
                result.append(meta_result)

        resp.text = json.dumps(result)


class NotificationItem:
    def __init__(self):
        pass

    @staticmethod
    def on_options(req, resp, id_):
        _ = req
        resp.status = falcon.HTTP_200
        _ = id_

    @staticmethod
    def on_get(req, resp, id_):
        """Handles GET requests"""
        if 'API-KEY' not in req.headers or \
                not isinstance(req.headers['API-KEY'], str) or \
                len(str.strip(req.headers['API-KEY'])) == 0:
            access_control(req)
        else:
            api_key_control(req)
        if not id_.isdigit() or int(id_) <= 0:
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.INVALID_NOTIFICATION_ID')

        # Verify User Session
        token = req.headers.get('TOKEN')
        user_uuid = req.headers.get('USER-UUID')
        if token is None:
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.TOKEN_NOT_FOUND_IN_HEADERS_PLEASE_LOGIN')
        if user_uuid is None:
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.USER_UUID_NOT_FOUND_IN_HEADERS_PLEASE_LOGIN')

        cnx = mysql.connector.connect(**config.myems_user_db)
        cursor = cnx.cursor()

        query = (" SELECT utc_expires "
                 " FROM tbl_sessions "
                 " WHERE user_uuid = %s AND token = %s")
        cursor.execute(query, (user_uuid, token,))
        row = cursor.fetchone()

        if row is None:
            if cursor:
                cursor.close()
            if cnx:
                cnx.close()
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.INVALID_SESSION_PLEASE_RE_LOGIN')
        else:
            utc_expires = row[0]
            if datetime.utcnow() > utc_expires:
                if cursor:
                    cursor.close()
                if cnx:
                    cnx.close()
                raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                       description='API.USER_SESSION_TIMEOUT')

        cursor.execute(" SELECT id "
                       " FROM tbl_users "
                       " WHERE uuid = %s ",
                       (user_uuid,))
        row = cursor.fetchone()
        if row is None:
            if cursor:
                cursor.close()
            if cnx:
                cnx.close()
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.INVALID_USER_PLEASE_RE_LOGIN')
        else:
            user_id = row[0]

        # get notification
        query = (" SELECT id, created_datetime_utc, status, subject, message, url "
                 " FROM tbl_notifications "
                 " WHERE id = %s AND user_id = %s ")
        cursor.execute(query, (id_, user_id))
        row = cursor.fetchone()

        if cursor:
            cursor.close()
        if cnx:
            cnx.close()

        if row is None:
            raise falcon.HTTPError(status=falcon.HTTP_404, title='API.NOT_FOUND',
                                   description='API.NOTIFICATION_NOT_FOUND')

        meta_result = {"id": row[0],
                       "created_datetime":
                           (row[1] +
                            timedelta(hours=int(config.utc_offset[1:3]))).isoformat()[0:19],
                       "status": row[2],
                       "subject": row[3],
                       "message": row[4],
                       "url": row[5]}

        resp.text = json.dumps(meta_result)

    @staticmethod
    @user_logger
    def on_put(req, resp, id_):
        """Handles PUT requests"""
        admin_control(req)
        try:
            raw_json = req.stream.read().decode('utf-8')
        except Exception as ex:
            print(str(ex))
            raise falcon.HTTPError(status=falcon.HTTP_400,
                                   title='API.BAD_REQUEST',
                                   description='API.FAILED_TO_READ_REQUEST_STREAM')

        if not id_.isdigit() or int(id_) <= 0:
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.INVALID_NOTIFICATION_ID')

        new_values = json.loads(raw_json)

        if 'status' not in new_values['data'].keys() or \
                not isinstance(new_values['data']['status'], str) or \
                len(str.strip(new_values['data']['status'])) == 0 or \
                str.strip(new_values['data']['status']) not in ('unread', 'read', 'archived'):
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.INVALID_STATUS')
        status = str.strip(new_values['data']['status'])

        # Verify User Session
        token = req.headers.get('TOKEN')
        user_uuid = req.headers.get('USER-UUID')
        if token is None:
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.TOKEN_NOT_FOUND_IN_HEADERS_PLEASE_LOGIN')
        if user_uuid is None:
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.USER_UUID_NOT_FOUND_IN_HEADERS_PLEASE_LOGIN')

        cnx = mysql.connector.connect(**config.myems_user_db)
        cursor = cnx.cursor()

        query = (" SELECT utc_expires "
                 " FROM tbl_sessions "
                 " WHERE user_uuid = %s AND token = %s")
        cursor.execute(query, (user_uuid, token,))
        row = cursor.fetchone()

        if row is None:
            if cursor:
                cursor.close()
            if cnx:
                cnx.close()
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.INVALID_SESSION_PLEASE_RE_LOGIN')
        else:
            utc_expires = row[0]
            if datetime.utcnow() > utc_expires:
                if cursor:
                    cursor.close()
                if cnx:
                    cnx.close()
                raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                       description='API.USER_SESSION_TIMEOUT')

        cursor.execute(" SELECT id "
                       " FROM tbl_users "
                       " WHERE uuid = %s ",
                       (user_uuid,))
        row = cursor.fetchone()
        if row is None:
            if cursor:
                cursor.close()
            if cnx:
                cnx.close()
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.INVALID_USER_PLEASE_RE_LOGIN')
        else:
            user_id = row[0]

        cursor.execute(" SELECT id "
                       " FROM tbl_notifications "
                       " WHERE id = %s AND user_id = %s ", (id_, user_id))
        if cursor.fetchone() is None:
            if cursor:
                cursor.close()
            if cnx:
                cnx.close()
            raise falcon.HTTPError(status=falcon.HTTP_404, title='API.NOT_FOUND',
                                   description='API.NOTIFICATION_NOT_FOUND')

        update_row = (" UPDATE tbl_notifications "
                      " SET status = %s "
                      " WHERE id = %s ")
        cursor.execute(update_row, (status,
                                    id_,))
        cnx.commit()
        if cursor:
            cursor.close()
        if cnx:
            cnx.close()

        resp.status = falcon.HTTP_200

    @staticmethod
    @user_logger
    def on_delete(req, resp, id_):
        admin_control(req)
        if not id_.isdigit() or int(id_) <= 0:
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.INVALID_NOTIFICATION_ID')

        # Verify User Session
        token = req.headers.get('TOKEN')
        user_uuid = req.headers.get('USER-UUID')
        if token is None:
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.TOKEN_NOT_FOUND_IN_HEADERS_PLEASE_LOGIN')
        if user_uuid is None:
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.USER_UUID_NOT_FOUND_IN_HEADERS_PLEASE_LOGIN')

        cnx = mysql.connector.connect(**config.myems_user_db)
        cursor = cnx.cursor()

        query = (" SELECT utc_expires "
                 " FROM tbl_sessions "
                 " WHERE user_uuid = %s AND token = %s")
        cursor.execute(query, (user_uuid, token,))
        row = cursor.fetchone()

        if row is None:
            if cursor:
                cursor.close()
            if cnx:
                cnx.close()
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.INVALID_SESSION_PLEASE_RE_LOGIN')
        else:
            utc_expires = row[0]
            if datetime.utcnow() > utc_expires:
                if cursor:
                    cursor.close()
                if cnx:
                    cnx.close()
                raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                       description='API.USER_SESSION_TIMEOUT')

        cursor.execute(" SELECT id "
                       " FROM tbl_users "
                       " WHERE uuid = %s ",
                       (user_uuid,))
        row = cursor.fetchone()
        if row is None:
            if cursor:
                cursor.close()
            if cnx:
                cnx.close()
            raise falcon.HTTPError(status=falcon.HTTP_400, title='API.BAD_REQUEST',
                                   description='API.INVALID_USER_PLEASE_RE_LOGIN')
        else:
            user_id = row[0]

        cursor.execute(" SELECT id "
                       " FROM tbl_notifications "
                       " WHERE id = %s AND user_id = %s ", (id_, user_id))
        row = cursor.fetchone()

        if row is None:
            if cursor:
                cursor.close()
            if cnx:
                cnx.close()
            raise falcon.HTTPError(status=falcon.HTTP_404, title='API.NOT_FOUND',
                                   description='API.NOTIFICATION_NOT_FOUND')

        cursor.execute(" DELETE FROM tbl_notifications WHERE id = %s ", (id_,))
        cnx.commit()
        if cursor:
            cursor.close()
        if cnx:
            cnx.close()

        resp.status = falcon.HTTP_204
